1. Field of the Invention
The present invention relates to driver circuits and, more particularly, is directed towards driver circuits for electric staplers and the like.
2. Background of the Invention
A variety of control circuits have been designed for actuating electrically operated stapling devices. For example, U.S. Pat. No. 4,333,019 discloses a silicon controlled rectifier driver circuit for an electric stapler. The patented driver circuit is responsive to an input AC voltage and is designed to provide at least one drive pulse to the stapler's load circuit for each activation of the stapler's trigger switch. Under certain conditions of high line noise, such as power tools on the line, a drive pulse may fire the patented stapler even though the trigger switch has not been activated. Furthermore, prior art stapler driver circuits suffer from the disadvantage of multiple firings within a fraction of a second because of switch bounce or multiple activations of the switch. Firing for multiple cycles of the line voltage causes overheating. A need has arisen for an improved driver circuit.